Just in case anyone reads that a fix is to disconnect the main battery momentarily - this is just clearing the error codes from the engine computer. The underlying problem is still there, and will eventually resurface.

Our '04 civic hybrid recently started having problems close to 80K miles. Battery replaced with remanufactured one by the dealer. A couples months and a few thousand miles later, a similar problem with the CEL comes on - but the battery still appears to be charging/discharging OK. Dealer is replacing the battery yet again, hopefully this time it will be longer than a few months...